Location-based coupons from Sports Authority, Eye-Fi and more

Are you ready to trade your current location for a discount? If you are, there are plenty of retailers looking to take you up on the trade with coupons, special deals and more. Services like Foursquare, Loopt and Gowalla are in an arms race to sign up users, and in partnership with advertisers, are giving away coupons and savings to individuals who check in to their favorite stores.

To take advantage of these offers, sign up for one of the services and download the app to your mobile phone. After you have it installed and are logged in, you simply tap on "check in" the next time you visit Sports Authority, Starbucks, Best Buy, Apple and other retailers large and small to unlock discounts.

Location-based discounts work in different ways, but like a loyalty card, you get points when you visit a place of business. With Foursquare, if you are the most frequent visitor then you are made "mayor" of the establishment. Becoming the mayor could take two trips or 20; it just depends on who has visited before you. Some offers, like the coupon from Sports Authority, require you to be mayor to get the discount, while others, like the Eye-Fi giveaway on Gowalla and Loopt coupons, only require a small number of visits.